Extracellular Polysaccharide Production by Rhizobium Sp. Nodulating Macrotyloma uniflorum (Lam.) Verdc

The ability of thirty two Rhizobium strains, isolated from ischolar_main nodules of Macrotyloma uniflorum (Lam.) Verdc. were tested for their production of extracellular polysaccharides (EPS) in Yeast Extract Mannitol (YEM) medium. Among the thirty two isolates, maximum amount of EPS was produced by the isolate HGR12 (4690 μg mL^-1). Both growth and EPS production started simultaneously. The production of EPS was maximum in the stationary phase of growth (72 hr) when the medium was supplemented with mannitol (1%). The EPS contained glucose, galactose, xylose, rhamnose and raffinose, which were identified by paper chromatography.